GMT to EST time converter

How far apart are London and New York?

It depends on the date. New York is 5 hours behind London while London is on GMT and New York on EST, or London is on BST and New York on EDT. New York is 4 hours behind London while London is on GMT and New York on EDT. The exact dates for 2026 and 2027 are below, worked out from the same time zone database your browser uses — not remembered.

2026

2027

GMT to EST hour table

Every hour of a London day, read across to New York — one column per gap, so pick the column for today's date from the table above. A row marked +1 day is already tomorrow there; −1 day is still yesterday.

Each column is one value of the gap; the clock names under it are the ones in force when that gap applies. For a half-hour time or a third city, use the timeline above: every clock moves to the instant you pick.

Working across London and New York

London and New York are five hours apart for most of the year, and this is the pair where the exceptions are the interesting part. Both countries observe daylight saving, so you might expect the gap never to move — and it would not, if they changed on the same day. They do not. The United States goes forward on the second Sunday in March; the United Kingdom waits until the last Sunday in March. In autumn the UK goes back on the last Sunday in October and the US on the first Sunday in November. For the two or three weeks in between each spring, and the one week each autumn, New York has moved and London has not, and the difference is four hours instead of five.

Those weeks are when standing transatlantic meetings quietly break. A call fixed at 3pm London and 10am New York is fine for forty-eight weeks of the year; in the gap weeks it is 3pm and 11am, and whichever side did not set the invite finds it an hour off. The table above prints the exact dates for this year and next, computed from your browser's own time zone database rather than from memory; the tool shows it live, and dragging across the second Sunday in March on the New York band shows that day being twenty-three hours long.

The abbreviations do not help. "GMT" is what London keeps only in winter; from late March to late October London is on British Summer Time, UTC+1. "EST" is what New York keeps only in winter; the rest of the year it is on Eastern Daylight Time, UTC−4. So "GMT to EST" is precise in January and mislabelled in July, when the honest pair is BST to EDT. The offsets happen to move together, which is why the difference is still five hours — but a converter that takes the letters literally will give a four-hour answer in summer that is wrong for both cities. The tool above uses Europe/London and America/New_York and applies whichever rule is in force on the day shown.

The working-day overlap is the best of any transatlantic pair. New York's 9am is London's 2pm, so the whole of a New York morning sits inside a London afternoon, and a meeting anywhere between 9am and 12pm Eastern lands between 2pm and 5pm in the UK. Deadlines cross the day boundary only late: it is already tomorrow in London from 7pm New York time, which is the usual reason a "tonight" from the American side arrives as a "this morning" in Britain.

One more thing that catches people out: the rest of Europe changes clocks on the same Sundays as the UK, so everything on this page about the timing of the gap weeks applies equally to Paris, Berlin and Madrid against New York — just with the difference one hour larger. Add a European city in the tool above to see it on the same timeline.

Sources

The offsets, dates and hour tables above are computed when this page is built, from the time zone rules your browser itself ships. The rules come from:

• IANA Time Zone Database — the rules every browser ships
• GOV.UK — When do the clocks change?
• NIST — Daylight Saving Time rules (United States)
• ECMA-402 — the Intl.DateTimeFormat standard these figures are computed with